• Journal of KIISE
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• v.42 no.11
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• pp.1430-1440
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• 2015

In contrast with battery-based wireless sensor networks (WSNs), solar-powered WSNs can operate for a longtime assuming that there is no hardware fault. Meanwhile, a mobile sink can save the energy consumption of WSN, but its ineffective movement may incur so much energy waste of not only itself but also an entire network. To solve this problem, many approaches, in which a mobile sink visits only on clustering-head nodes, have been proposed. But, the clustering scheme also has its own problems such as energy imbalance and data instability. In this study, therefore, a cluster-based energy-aware data-sharing scheme (CE-DSS) is proposed to effectively support a mobile sink in a solar-powered WSN. By utilizing the redundant energy efficiently, CE-DSS shares the gathered data among cluster-heads, while minimizing the unexpected black-out time. The simulation results show that CE-DSS increases the data reliability as well as conserves the energy of the mobile sink.

• JOURNAL OF ELECTRICAL WORLD
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• no.9 s.10
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• pp.15-18
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• 1976

석탄이나, 석유, 우라늄 같은 자원은 한계가 있다. 지구상의 인류가 존재하는 데에 필요한 에너지원의 문제를 해결하기 의해서는 해수중의 중수를 연료로하여 조그만 태양같은 것을 지구위에 만들어 놓으면 된다. 이것의 핵융합로인데 약 100억년이나 공급할 수 있다는 계산이 된다. 기술적으로는 어렵겠으나 지금까지 이 연구실적으로 우리나라도 세계의 제1선과 나란히 자주개발이 가능한 것이다.

• Environmental and Resource Economics Review
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• v.31 no.2
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• pp.141-163
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• 2022

This paper empirically analyzes the effect of renewable electricity generation on the System Marginal Price (SMP) in Korea. Using an ARX-GARCHX model with hourly data from 2016 to 2020, we evaluate SMP determinants and merit order effects. As a result, we find that solar and wind power, as well as gas price and total load, play a critical role in the SMP. In particular, solar power reduces the SMP level but raises volatility during peak and off-peak periods. This result implies that SMP may fall as renewable electricity generation increases, leading to a decrease in the profitability of existing power plants and investment in renewables. On the other hand, even if the subsidy of renewable energy increases the burden on the SMP, it can be offset by the merit order effect, which lowers the SMP.

• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.29-35
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• 2007

In accordance with Madrid and Kyoto Protocols, a 10kw wind turbine installed about 625m away from the King Sejong Station in the Antarctica has been in operation successfully. The current location of the wind turbine has different geographic surroundings from the previous candidate site considered in 2005 and that makes re-evaluation of wind resource at the current site including geographic effects necessary. Especially, strong wind flow derived by steep and complex terrain is dominant in the Antarctica so that computational flow analysis is required. The wind rose measured at the previous and current installation location are identical with strong meteorological correlation but prevailing directions of wind power density are different because of local wind acceleration due to complex terrain. Numerical analysis explains which effects brings this discordance between the two sites, and a design guideline required for additional wind turbine installation has been secured.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.235-238
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• 2009

It is necessary to estimate empirical constants in order to predict the monthly mean daily global radiation on a horizontal surface in the developing areas for alternative energy. Therefore many different equations have proposed to evaluate them for certain areas. In this work a new correlation has been made to predict the solar radiation for any areas over Korea by calculating the regression models taking into account latitude, percentage of possible sunshine, and cloud cover. From the results, the single linear equation proposed by using percentage of possible sunshine method shows reliable results for estimating the global radiation with average annual deviation of -3.1 to +0.6 % from measured values

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.310-313
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• 2008

The wind resource potentials of South Korea are estimated as preliminary stage using the national wind map which has been being established by numerical wind simulation and GIS (Geographical Information System) exclusion analysis. The wind resource potentials are classifying into theoretical, geographical, technical and implementation potentials and the calculation results are verified by comparing to other countries' potentials. In GIS exclusion, urban, road, water body, national parks and steep slope area are excluded from onshore geographical potential while water depth and offshore distance from the shoreline are applied s offshore exclusion conditions. To estimate implementation potential, dissemination records of European countries are adopted which is about 1/8 of geographical potential.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.322-326
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• 2008

This paper presents an estimation method of small hydro power(SHP) potential using a SHP resource map. As a basic unit of SHP energy potential at a certain area, capacity and annual energy production of unit head was calculated from the catchment area given by a SHP resource map which was established by numerical hydrologic simulation so that a logical and relatively accurate potential estimation was possible comparing with the performance analysis model for SHP sites. The performance characteristics for Samok-Ri site were analyzed, using the SHP resource map and the developed model. It was found that the SHP resource map and the developed model is useful tool to estimate SHP potential.

• Journal of the Korean Solar Energy Society
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• v.28 no.6
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• pp.1-7
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• 2008

The wind resource potentials of South Korea are estimated as preliminary stage using the national wind map which has been being established by numerical wind simulation and GIS (Geographical Information System) exclusion analysis. The wind resource potentials are classifying into theoretical, geographical, technical and implementation potentials and the calculation results are verified by comparing to other countries' potentials. In GIS exclusion, urban, road, water body, national parks and steep slope area are excluded from onshore geographical potential while water depth and offshore distance from the shoreline are applied as offshore exclusion conditions. To estimate implementation potential, dissemination records of European countries are adopted which is about 1/8 of geographical potential. The implementation potential of South Korea would correspond 12.5GW which is 1.7 times of the national wind energy dissemination target until 2030.

• Journal of the Korean Solar Energy Society
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• v.23 no.2
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• pp.35-41
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• 2003

In order to investigate the offshore wind resources around Korean peninsula, the "QuikSCAT Level 3" data by ADEOS II satellite was analyzed from Jan 1 2000 to Jan 18 2003. The "SeaWinds" on the satellite is a specialize4 device for microwave scatterometery that measures near-surface wind speed and direction under all weather and cloud conditions. Wind speed are extrapolated from 10m to 60m with the exponent of 1/10 in the power law model. It has been found that the High wind energy potentials are prevailing in the South sea and Southeastern end of Korean peninsula.

• Journal of the Korean Solar Energy Society
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• v.28 no.2
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• pp.42-49
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• 2008

제주 행원 풍력발전단지 내의 풍력발전시스템을 대상으로 연도별 풍력발전시스템의 운전특성과 고장원인이 분석되었다. 이용된 데이터는 2005년과 2006년 4월에서 9월 사이의 기상데이터와 풍력발전기의 운전데이터이다. 그 결과, 풍력자원은 해에 따라 변동이 있음을 확인할 수 있었고, 풍력발전기의 발전량 역시 해에 따라 변동함을 알 수 있었다. 또한 풍력발전기의 고장 또는 정지로 인하여 발전량이 떨어지고 있음을 확인하였고, 후류로 인한 발전량 손실도 추정할 수 있었다. 같은 해에 풍력발전기 1, 2호기를 운전 개시하였지만, 고장 또는 정지원인은 일관성이 없이 다양함을 알 수 있었다. 이 연구에서 시스템이 가장 많은 시간동안 정지한 원인은 기어박스와 요잉장치의 고장으로 분석되었다.